Technical Discussion

Synopsis:

A clipper system looks like it will bring some snow showers to western and northern Pennsylvania.  The track of the big system is still in question, but a westerly solution looks to be in great favor.  Another perfect lake-effect snow setup for next week.

Short-term:
Radar images from this evening have shown numerous light snow showers far east of where the snow begins at the surface.  SREF precip type indicates snow down to Pittsburgh and out to Johnstown and State College, as well as Erie and Bradford.

Long-term:

The GFS is quicker and more defined with the FroPa through western Pennsylvania, while the WRF seems to get caught-up in the merger of the Lakes low and the Coastal low.  The timing of the cold front is the timing of the snow, as temperatures ahead of the cold front appear to be just above freezing except at higher elevations.  We generally favored the GFS because its solution looks more natural.

Deep low-level moisture can be seen with the lake-effect snow on the east-west border between Erie and Bradford, almost like there is a mixing layer that extends to 700mb.  This to me is unusual, so I thought the best assumption was that this means heavy snow.